Testing the Waters
by Pixelated Optimism
Summary: Her growth spurt started to fuck his life.
1. Chapter 1

**Testing the Waters**

**Author: Pixelated Optimism**

_ Her growth spurt started to fuck his life._

* * *

Rin, contrary to popular belief, wasn't just a set of shark teeth. He was a boy, a boy with a heart, a heart acute to all emotions, emotions including affection and murder.

True, he might not be the likes of Nagisa, who was altogether made of soft, mushy fluff it was a wonder how he could stay at water in one piece, or that clown freak Makoto who never got tired of smiling, and definitely not like Haru, whose emotions were so alienated he chose to portray them stoically. No, he was way beyond that. In fact, he believed he was made of more than all of them.

But he wasn't altogether complex. Rin liked to believe that he was simple. When he was angry, he was simply angry and when Rin is angry, it was sure that his fists would fly into someone else's face. When he was happy, well, he might not grin a lot, but he'd smile too, especially when Gou would crack a joke or two. When he was sad he'd chose a far corner of a room or better yet some deserted pool and he'd dive in and do laps until he was out of breath.

He was simple.

But Gou was another story. If only girls were so simple like this, life could've been easier, but no, they weren't. Gou was a girl, and Gou was as complex as any breathing technique he encountered.

Partially he blamed her. Gou liked to follow him around since they were little, always tugging the hem of his shirt, always asking if he was fine or not, always worrying about him. He was basked with her love and attention, and he liked it, loved it, possessively owned her. He was spoiled in the most likely terms by his baby sister.

But that was way back then, before she started growing up.

It was late when he realized she was gaining looks because she'd grown an ass and her shirt had been too tight for her chest.

Her growth spurt started to fuck his life.

She was Gou. He was hers. No one's going to lay a finger on his baby sister. Not a fucking chance at all.

Until she foolishly became Iwatobi's manager.

At first Rin thought it would be perfectly innocent. Haru was nowhere interested in girls, as far as he knew. He was too sexually in love with water for the moment. Nagisa was a great teddy bear to be interested in girls too. Rei. . . Rei was too serious for silly things like girls, and Makoto, that smiling freak, was too immersed being a smiling captain to Iwatobi to mind someone attractive like his baby sister existing.

How fucking son of bitches they are.

* * *

It started with that cutesy stupid pet names.

He was flipping through random channels seemingly one ordinary Sunday morning when his baby sister walked in front of him, sporting a red one piece bikini. Grinning, she twirled around, as if to proudly show him how cute she was.

"How was it, Ni-san?" she pouted. As much as Rin liked to sing praises to Gou, encouraging her would only make things worse. He was sure she'd wear them on some random beach and boys would be sure to swarm around her, so instead he shrugged.

"Too red" he grumbled under his breath. Gou pouted.

"Ama-sensei said it's cute" she said "Mou, Nagisa-san said it suits me. Mako-kun even said I looked good with red"

He easily shrugged. Makoto was a real slacker—

_Wait._

_What?_

_Mako?_

_Gou called Makoto Mako?_

He looked at her as she absentmindedly pulled some of her burgundy strands straying on her shoulder, her eyes bordered on some oblivion nonexistent to him.

_Mako?_

Since when did they become so intimately close? Rin didn't really want to mind, since everyone had affectionately called the captain of the Iwatobi _Mako._ But it was a different thing now since it was Gou. Gou in the first place is his baby sister, and Gou is a girl, and Gou, his baby sister, calling some stupid, pool freak guy by his cutesy nickname . . .

He would kill that damn freak. He would really, _really _kill him.

"Oh, I nearly forgot. Mako-kun says hello to you" she said over her shoulder as she went for the stairs.

* * *

As if that stupid cutesy pet name wasn't enough to set Rin off the edge, phone calls started pestering his life.

He was on his way to the kitchen for some water when he heard Gou's animated little voice on the phone. Intrigued on who might be calling his baby sister so late in the evening, he leaned on her bedroom door and took the risk of eavesdropping

"Haru-senpai, I told you it's better with tomatoes" she hissed. A moment of silence, he heard her sigh exasperatedly.

"Mou, Haru-senpai. You like mackerel too much, you know"

Giggle. Silence, then another giggle.

"No, I don't want a mackerel. But, yeah, I do think that a treat after school sounds better too"

A snicker, then another giggle.

"That's a deal then, no take backs!"

It took a lot of effort not to punch a hole in the wall. The next time he sees Haru, he'd make sure he'd carve a hole in his motherfucker's face.

* * *

If he could only box his baby sister inside him, he would definitely do so. But he can't. And so he gritted his teeth.

Rin could only mutter fuck consecutively at the sight before him. Seijuuro was blushing, the good for nothing son of a bitch was smiling upon the sight of his baby sister.

Fuck.

If that fucking whore Seijuuro wouldn't stop showing his abs with that sick perverted smile of his then he'd sooner run because he wouldn't mind showing the birdbrain his _other _side. The hell with him being the captain! He could swim better than him, for heaven's sake! And why Gou of all people? There are hell bent girls crazy for him, why would he choose his baby sister?

"Ni-san?" her voice peeked through his clouded thoughts. Rin spat angrily before he turned at her.

"Why are you here?" he said as he cracked his knuckles. There was no way Seijuuro would hit his baby sister so easily.

"I was actually spying" she giggled. "Iwatobi would be better with a handful of juicy information from other schools, ne?"

He scoffed. She really didn't need to. Makoto and Haru would be as ruthless as competition with or without information.

"I'm sure we would be your toughest competition, Gou-chan" Seijuuro butted in. When she faced and gave him a warm smile Rin had to eat away his rage as he saw his cheeks positively turned beet red.

Fuck all of them.

There was no way Gou would be laid. No one would hit her, not until Rin Matsuoka lives.

Or so he thought.

* * *

_This fandom's killing me literally._

_I'd be happy and kill a hundred Titans if you could review~_

fangirling over Levi Rivaille \(*U*\)

おつみる ばけもの


	2. Chapter 2

**Testing the Waters **

**Author: Pixelated Optimism**

_Her growth spurt started to fuck his life._

* * *

Rin knew he wasn't as sharp as his shark teeth.

For the glory of Seijuuro Mikoshiba's butt he knew he was not particularly bright in socializing with people. In fact he could be the worse. The only thing Rin knew he was sharp at was his stingy mouth, well, swimming set aside.

He was particularly cold, defiant and stubborn. He was bloody insensitive, a true selfish jerk. But he's not that dense. Maybe it was the big brother genes, how he and his baby sister shared half of each other, maybe not, but despite him shrugging off Gou's existence sometimes, there remained a part of him that would always know instinctively.

He knew, the way her eyes sparkled, her breath hitch, her cheeks blush. It wasn't just a simple crush.

Gou, his baby sister, adored someone.

Rin should've cared less. Girls would always be girls. Crushes are normal part of growing up. But Gou was different. She's a bit weird, and her choice limits are due to the fact that Rin was a swimmer. If there were particular candidates, it would be the swimmers around her. _Iwatobi members_ and _one fucking stalker_ for instance.

So unlike any other day as he strolled his way to Gou he tried to analyze what would her baby sister liked in a stupid guy.

It wasn't the muscles, he was pretty sure of that. For all Rin cared Gou showed almost the same fangirling over Makoto's biceps and Nagisa's deltiods and Rei's triceps and yeah, for that lecherous Seijuuro's pectorals also. Gladly he could've stripped and force her fetish out. But muscles are petty, and Gou wasn't the type to fall over for a lump of meat. It wasn't the muscles.

It wasn't the swimming skills also. He could've topped her list with no sweat, seeing Makoto was just a piece of cake and Haru was definitely way below him, not to mention Nagisa and Rei are no match for his mean freestyle and that fucker Seijuuro, albeit his new records and established name, appear a small pudgy goby fish beside him. No, it wasn't the skills.

It wasn't the face too. He had to admit Seijuuro looked cool enough with his damn phoenix hair, but Gou hated red. Makoto and his smiling, fucking calm face were in no ways near Gou's interests. Nagisa's cute antics could work on other girls but not on her baby sister. Rei . . . Rei's a bit mechanical and Rin doubted if Gou liked boys with glasses. Haru's face was always stoic. He was way better, way way better than all of them. Yes, it's not the face either.

Well, not that Rin could do anything, he could kill the damn freak, for all he cared. But things would stay just the same. His baby sister would sooner or later give her whole cute damn affection to some random pool freak and he'd be left alone.

He wondered what was the bitter taste creeping on his tongue was.

* * *

"I'm ho—?"

Two pairs of bright eyes welcomed him as he opened the door. Rin blinked hard. Fucking fuck.

_Ren _and _Ran._

_What the bloody hell are they doing in my house?!_

For a moment Rin thought this was just a part of the grand scheme of universe to fuck with him. It was a rather weird day to start off. That asshole Seijuuro dismissed swimming practice early, Nitori his lovely remora kicked him out of their dorm for some serious spring cleaning and Nagisa texted him one of his stupid linked messages. Sure, this might be some fucking joke? There was no way Makoto's twin siblings stand in front of his own doorsteps?

"Uwaa, Rin-nii-chan!" Ren piped up as Ran giggled and ran to hug him, her little arms failing to encircle his waist. Rin stood, transfixed, before a playful tug on his jersey sent him back. Expectant eyes looked at hm.

"Eh . . . it's good to see you two" he awkwardly said, not sure where to start. Ren gave a chortle.

"Come and play with us, Rin-nii-chan!" Ren said breathlessly as he jumped into his arms. With a pout, Ran tugged at his sleeve and added "We could cook mackerel for you, just like what Haru-nii-chan taught us a while ago!"

"Yes" perked Ren on his arms "You could join us in the tent! We're doing sleepovers!"

Completely lost as to what to do, he carried Ren and held Ran close, steering them inside. It took no genius to tell what was happening.

Makoto _was_ there.

Haru was there as well.

_Fucking hell_.

Why the sudden visit?

Of course Rin knew he hasn't anything to say about visits or sleepovers. It was Gou and his mother's house. After all he's comfortably staying at Samezuka's dorm, but he was her brother, and he was a Matsuoka as well. Technically he must have some sort of entitlement as to who has the rights to go in and out of her baby sister's place? It wasn't as if Gou's friends are a bunch of girls. They're pheromone-filled boys, for fuck's sake. Being Iwatobi's Captain or member does not give them enough perks to do visits and sleepovers with his baby sister.

Gou was still a girl. A very pretty girl. Not just Iwatobi's manager. She was his baby sister.

Musing as to how to make his house free from boys he felt Ren's arms tightened around his neck and Ran's little fingers curling around his large hand. Looking down he saw her put her index finger on her lips cutely.

"They've been sleeping since who knows when" Ren whispered, pointing at the sitting room where a blue shark printed tent was propped up, orca and dolphin plushies littering the floor along with discarded Pocky boxes and _the damn freak and that stupid mackerel psycho and his baby sister._

Rin felt a flash of fury.

It took all of his energy not to throw Ren and push Ran aside.

Makoto looked calm, his chin perched on Gou's head, his right arm outstretched. Gou was sleeping peacefully, her mouth slightly open, her head leaning on Makoto's large shoulder, her left arm rested on his broad chest, a slight flush dusted her cheeks, her trademark Matsuoka hair spilling on her shoulders, Haru easily behind her, his serene face partially buried on Gou's tousled hair. His arms loosely wrapped around her waist.

"We played truth or dare!" giggled Ran. "Then they fell asleep"

"Ni-chan and Kou-nee-chan look _good_ together" Ren piped, Ran pouted.

"Haru-nii-chan and Kou-nee-chan looked _better_!"

_"Ni-chan!"_

_"Haru-nii-chan!"_

_"Ni-chan!"_

_"Haru-nii-chan!"_

"Fine" Ren huffed, crossing his arms "Kou-nee-chan said she likes boys with _glasses. _Ni-chan wears glasses!"

Rin's stomach did a back flip. _Fuck._

"Oh really?" Ran countered back. "Kou-nee-chan said she likes someone who can cook. Haru-nii-chan can cook!"

He tried to look at his baby sister, snuggling close to those damn freaks, and wondered how she could easily fit in their arms. _Fuck._

"Well, maybe Ni-chan and Haru-nii-chan could share Kou-nee-chan, ne, Rin-nii-chan?" asked Ren. Rin sighed and scoffed.

"I wear glasses and I can cook" he lied, smirking as he put Ren down "Maybe Kou-nee-chan likes me"

Ren and Ran looked at each other. Rin bit the bitter taste creeping on his mouth.

_Fuck this thing called jealousy_.

* * *

_Yes this is a bit fluff and yes you could kill me for the late update, offer me to the Titans please~_

School's out so I've got three weeks free time yay! I never thought this would garner so much attention, seeing that the first chapter was too random and honestly I had a hard time thinking a follow up. But there, I pencil-pushed my way. I give all the love and Titan hugs to every amazing people who reviewed and hit the fave and follow buttons, you don't have any idea how you guys made me roll on the floor and yes, I admit I am now in shipping crisis. Mako is cute and Haru is sexy and Rin is adorable and dear Mikoshiba is just . . . *sigh*

sorry if this is a bit sloppy, but I will try my very best on the next chapters.

singing a petition for Free! and Shingeki no Kyojin's 2nd Season \(OvO)/

おつみる ばけもの


	3. Chapter 3

**Testing the Waters **

**Author: Pixelated Optimism **

_ Her growth spurt started to fuck his life._

* * *

Rin had always and _firmly_ liked to believe he was as tough as his hide.

It wasn't that simple, but it wasn't that hard either. If you were born with a talent of showing snarky arrogance and mean freestyle and you have diligently practiced your cold stare and menacing shark grin acting tough and fearless would be just a breeze for you, and fortunately Rin had it all. In fact, he still wondered how that goby fish captain of his maintain that stupid smile every time he was around, or how Nitori could still endure his company, or how Nagisa could still have the nerve to send him sweets and linked messages and Makoto beam at him like he wore a fucking flower crown of sunshine on his head and all.

He may be slacking off a little bit.

But that doesn't change anything, no matter how many stupid smiles or stretch of patience, sweets, linked messages and beams they shower him Rin would stay as stiff as stone, full of apathy and indifference, thank you very much. If they are waiting for that special cursed time when he'd grow a heart to mind all the people who give a damn fuck about his business he might as well break that sorry news that it would never ever happen.

Nothing could bend him. _Nothing at all_.

Of course there were special occasions when he was pestered to eat his own words, like when that fucking Seijuuro forced him into that equally fucking stupid maid uniform. He sure did agree, but it came with a heavy price. Mikoshiba _fucking_ Seijuuro already topped his _to kill_ list because of that, which is also pretty convenient since that goby fish was hitting first base with his precious baby sister.

But that was the last time he'd let his guard down. He wouldn't say yes to preposterous fucking stuff again, he swore to that.

So when Gou smiled at him like he was her everything, he sighed. Nagisa clapped his hands, Rei shook his head and muttered something, Haru mumbled about mackerel, Makoto hid a small chuckle behind his fist, Seijuuro blushed, and Nitori squirmed beside him.

"We're playing house!" Nagisa giggled, his eyes glittering with devilish cunning. Rin had only one word running beneath his tongue.

_Fucking fuck._

He held patience, quite surprising because Makoto and Haru could've been dead even before touching the tip of Gou's hair, but for the sake of Ran and Ren he said nothing. It was an innocent sleepover, with kids and two hormone enraged boys and his pretty growing baby sister. Perfectly _normal_. In fact, after he sent Ran and Ren to sleep with their plush orcas and sharks and dolphins in arm in his own room he managed a straight face, shaking Gou and the clown freak and the water psycho out of their sleep.

How that fluffy teddy bear Nagisa and that mechanical Rei and the fucking lecherous goby fish Seijuuro and his little remora Nitori came into picture was something Rin found a wonder. As far as he was concerned, after Gou and Makoto and Haru woke up Nagisa came rapping at the door, gripping Rei's arms forcefully with Seijuuro and Nitori behind them, as if some unexplained force had brought them to his house and fuck and mess with his fucking life.

"Could I ask again why are _you_ here in _my_ house?" he asked. Nagisa smiled sweetly at him.

"Maa, Rin-chan. Aren't you happy we could play house again? Besides, Ren and Ran called me so we can join their sleepovers. It's mean to leave me and Rei-chan, really. It's an _Iwatobi Sleepover Party_!"

"Yeah, _Iwatobi_ my ass. What are _you _doing here?" he shrugged, pointing a dire finger at his captain who laughed and scratched the back of his head.

"There, there Matsuoka. Nitori and I are just on the way and we saw Nagisa-san so I thought—"

"—this would be a fucking perfect way to hit my baby sister, _fuck off—_"

"Ni-chan!"

Gou stood in front of him, biting her lip, hands both on waist which reminded him a little bit of their mom.

"If Nagisa-san invited Mikoshiba-buchou and Nitori-kun to our _Iwatobi Sleepover Party_ then we should welcome them"

"Since when did this stupid kid's sleepover become _Iwatobi's Sleepover Party_?" he snapped, glaring at Nagisa

"Since I announced it" she snapped back, huffing as she crossed her little arms over her chest. "Aren't you a bit happy we could spend time with your friends?"

Great, just fucking _great_.

All he wished that afternoon was sleep with Gou beside him, silence and a bit of peace to soothe his nerves. There wasn't anything about having Nagisa, Rei, Haru and Makoto or Seijuuro and Nitori in his house, with Gou pulling the strings, acting like it was her lifetime mission to reunite him with his old friends, as far as he can remember.

"Everybody agreed" she pointed out. "We're playing house, no take backs"

"This is stupid Gou—"

"It's not. You should be grateful all of them are here. This is really rare"

"We always see each other at joint practices, what's the big deal?"

"We don't play house at joint practices"

"Really Gou, do we look like seven year old kids to play house?"

By the looks of it, he won the argument. Gou looked flushed and breathed heavily.

"It's_ Kou_. Mako-kun would be mother"

"Gou-chan?!"

They all gagged except Haru, who pointed Rin with a steely glint on his blue eyes.

"Rin could be father" he said, making Seijuuro and Nagisa suppress a laugh.

"I'm out of here" Rei announced, but before he can so much step Nagisa had his arms around his neck.

"Rei can be grandpa since he has glasses" he animatedly said. "Haru-chan, you're grandma!"

Rei blushed and shoved his glasses.

"Mikoshiba-buchou could be the older brother" Nagisa added, "Nitori-kun would be baby brother"

"I'm not playing this stupidity" Rin spat, looking at Gou who breathed and scoffed at him.

"Then I'm playing Mikoshiba-buchou's _girlfriend_" she announced. Everybody froze. She could've just announced Rin's death, for all she cared. The stupid goby fish looked flustered, blushing and all and making it really worse.

"Hell, fucking no way, Gou" he murderously said.

She glared, her red cheeks puffing a bit. Her eyes bordered only against him.

Matsuoka Rin liked to believe he was always tough as his hide.

"Fine, I'll play" he sighed "But you're out of this Gou"

Yeah. He wore the toughest hide ever.

* * *

_*tears, sniff, tissues, tears*_

_Thank you all beautiful people who gave patience and reviewed and faved and followed this story. I am well aware that my story sounds pretty much an amateur oneshot fic and that I'm really trying to make every reader as comfortable as possible, and that I know I sometimes fall short of expectations but still, I am doing my best. I'm so sorry if I fail you, I'm so sorry if I disappoint you, but let me just say that I love you all with my whole hypothalamus. You guys haven't had the slightest idea how happy I am that there are people out there who appreciate fics like this one. People who are truly, freaking amazing for the hundredth time. I owe you a lot of my happiness right now. Thank you, thank you so much for everything. _

_forgive all the feels, I just felt like thanking you all guys like my death is nothing but impending._

_as for the shipping crisis, I was close to tears laughing with your direct and subliminal suggestions. It helped a lot, and yes, I have decided already. _

brimming with happiness while wiping my tears away *(/ TwT \)*

おつみる ばけもの


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